Air adjustment for gas burner



Aug. 20, 1957 c. w. NESBITT AIR ADJUSTMENT FOR GAS BURNER MANIFOLD Filed March 16, 1953 United States Patent AIR ADJUSTMENT FOR GAS BURNER MANIFOLD Clifford W. Nesbitt, Racine, Wis., assignor to Modine Manufacturing Company, Racine, Wis., a corporation of Wisconsin Application March 16, 1953, Serial No. 342,504

1 Claim. (Cl. 158-7) The invention relates generally to gas burner constructions and more particularly to gaseous fuel burning devices which include a casing or jacket which encloses the burner structure.

Many gas burning devices as, for example, modern home heating units, furnaces, portable home heating units, and unit heaters utilize a jacket or casing in which the entire structure is enclosed or housed. Such casings normally serve two functions: (1) to provide an ornamental structure for concealing the various elements of the device, and (2) to provide a protective enclosure or supporting structure for the various elements. The present trend in structures of this type is to completely enclose the heating unit including the burner structure, providing suitable openings in the casing or housing for the passage of the primary and secondary air necessary for proper combustion in the gas burner. It is common practice to form such openings in the casing, either in the form of grille work or the like, or in some cases, to place a separate grille before the opening. It will be apparent that in such constructions the openings for the admission of such air ordinarily are somewhat'restrictive, whereby the air pressure inside the casing tends to be lower than the pressure exteriorly thereof. Furthermore, as restricted openings of such type are employed, usually comprising a series of relatively small openings, panels or doors are employed to provide access to the gas burner and the adjustable elements associated therewith.

Obviously, it is highly desirable to accurately control the amount of primary air entering the gas burner which is mixed with the combustible gas to effect the most efficient-proportions between the volume of gas and volume of air being utilized in the burner itself. Similarly, in addition to such primary air, additional secondary air must be admitted to support ei'ficient combustion at and above the gas ports along the burner structure. To enable effective control the primary air admitted into the gas burner, the latter is normally provided with a movable cover member or the like, which may be adjusted with respect to the primary air intake opening of the burner, whereby the effective size of such opening may be varied and thus vary the amount of primary air into the burner. It has been common practice over a long period of time to utilize a rotatable cover plate which is provided with an opening therein which, by rotation of the plate may be positioned in alignment with the air intake opening of the burner or rotated to partially close such opening. In adjusting such a plate, it is necessary to have direct access to the burner structure on which the plate is mounted whereby the plate may be manually rotated. Where the burner structure is substantially completely enclosed, the casing must of necessity be provided with a panel or door which may be opened or removed to permit access to the one or more air adjustments on the burner. It will be appreciated that upon the opening of such a panel or door, new air intake paths or openings are produced through which the supporting air of combustion may flow. This action takes place throughout the period of adjustment of the primary air control member and following completion of the adjustments and closure or replacement of the door r panel, such supplementary air flow is cut off.

As a result of the above situation, the conditions under which the burner is adjusted are different from the conditions under which the burner normally operates so that the apparent desired proportions of gas and air admitted into theburner structure, as determined by the careful adjustment of the primary air, are upset or destroyed when the door or panel is closed, due to return of the air-pressure relations between the interior and exterior of the casing to their original, normal operating relationship. It will be apparent from the above that the most efficient adjustment of the burner is seldom obtained and, at best, the adjustment must be made inv an effort to anticipate the desired results when the door or panel is in closed position.

The present invention, therefore, has among its objects the production of a burner structure and casing which is'so designedthat the primary air into the gas burner may be adjusted under exact normal operating conditions whereby the necessary adjustments can be quickly and accurately made without upsetting the factors controlling combustion.

Another object of the invention is to provide a structure which is exceedingly simple in construction, inexpensive to manufacture, and which will insure uniform maximum efficiency throughout periods of use.

Many other objects and advantages of the construction herein shown and described will be obvious to those skilled in the art from the disclosure herein given.

To this end my invention consists in the novel construction, arrangement and combination of parts herein shown and described, andmore particularlypointed out in the claim.

In the drawing, wherein like reference characters indicate like or corresponding parts:

Fig. 1 is a horizontal sectional view through a gas burner structure and'casing utilizing the present embodiment; Fig. 2 is a sectional view. taken approximately on the line 22 of Fig. 1;

Fig. 3 is a sectional view taken approximately on the line 33 of Fig. 1.

The present invention contemplates the use of a burner and casing structure which is so designed that means for adjusting the primary air admitted into the burner may be readily adjusted and controlled from the exterior of the casing, eliminating any necessity to open sections of the casing to make such adjustments accessible, so that the relationship of the various elements of the burner and easing structure, and thus the relationship between the interior and exterior air pressures is not .dis-. turbed, and the air adjustment may be, made under the exact normal operating conditions. Referring to the drawings, the reference numeral 1 indicates generally a casing of the type used on unit heaters or the like, in which is positioned a gas burner unit, indicated generally by the numeral 2. In gas burning units of the type here involved, the burner structure is normally posia tioned adjacent the bottom of the unit with a suitable heat exchange structure being positioned thereabove through which the products of combustion flow and from which thye pass into a manifold which is normally connected to a stack for conducting such products of combustion to the outside of the building or enclosure heated by the unit.

The gas burner 2 may be of any suitable construction, that illustrated being similar to the burner structure disclosed in my vco-pendin-g application, Serial No. 337,480,

filed on February 18, 1953, and utilizes a tubular manifold 3 from which extend a plurality of burner tubes 4, the interior of which communicate with the manifold 3, each burner tube 4 having a series of burner ports 5 extending along the top portion thereof. Positioned within the manifold 3 is an air inspirator tube 6 having its inner end 7 engaged with the end wall 8 of the manifold and provided with a discharge opening 9 to provide communication between the manifold 3 and tube 6. The outer end of the tube 6 is provided with a flared portion 11 terminating at its outer edge in a flange 12 which is secured to the inner periphery of the manifold 2. Also secured to the flange 12 is a closure disc or plate 13 having a peripheral flange 14 secured to the flange 12 of the tube 6 and provided with an inwardly flanged axially positioned gas intake opening 15. The member 13 is also provided with an arcuate shaped opening 16 through which primary air may be admitted into the inspirator tube 6.

The primary air adjustment structure comprises an annular shaped member 17 which is provided with a tubular sleeve 18 of a size to enter the opening 15 in the member 13, and is provided at its periphery with an axially extending flange 19 of a size to be nested in the member 13 within the flange 14 thereof. The member 17 is provided with an arcuate shaped opening 17' similar in shape and size to that of the opening 16 and, as the member 17 is rotatable relative to the member 13, the effective size of the air intake opening may be readily adjusted by varying the co-extensive portions of the openings 16 and 17. Positioned between the outer face of the member 17 and the inner face of the casing 1, and encircling the adjacent portion of the sleeve 18 is a compression spring 20 operative to urge the member 17 toward and into engagement with the disc or plate 13.

As illustrated in Fig. l, the sleeve 18 is of a size to more or less snugly receive the gas discharge tube 21 which is provided at its inner end with a jet or nozzle 22 by means of which gas may be discharged from the supply pipe or member 23 to the interior of the ins irator tube 6. The sleeve 18, as clearly illustrated in Fig. 1, extends through an opening 24 in the side wall 26 of the casing 1 and is provided adjacent its outer end with a threaded boss 25 in which is threaded a set screw 27 which is engageable with the tube 21 and provides means for locking the sleeve 18 and member 17 in any of their adjusted positions.

As illustrated in Fig. l, the casing 1 includes side walls 26, a front wall 28, rear wall 29, and bottom 31. The burner structure 2 may be mounted within the casing 1 by any suitable means as, for example, a flanged bracket member 32 connected to the manifold 3, the flange 33 of which may be secured to the casing by any suitable means as, for example, spot welding. The ends of the tubes 4 in the embodiment of the invention illustrated are connected to a suitable cross member 34, the ends of which are suitably secured to the side walls 26 in the casing as indicated at 35. The respective side walls of the easing may be provided with suitable openings for the entrance of air into the casing and to the burner structure. Such openings may be of any desired shape, size, and number to provide an adequate volume of air to achieve efficient combustion and, in the construction illustrated, such openings are in the form of a series of slots 36 formed by slitting the side wall and deforming portions of the same inwardly to provide a series of louvers 37.

When the burner is in use, the primary air entering the inspirator tube 6 may be readily adjusted by backing off the set screw 27, following which the portion 18a of the sleeve 18 extending outwardly from the side wall of the casing may be manually grasped and rotated to vary the effective size of the primary air intake opening. Thus, the person making the adjustment may watch the burner action through the openings 36 and simultflfl6- ously adjust the primary air to provide the most eflicient combustion, following which the screw 27 is tightened to lock the members in their adjusted positions. Obviously, such adjustment is made without disturbing the physical or operative relationship between the burner structure, the casing, and related parts; and the adjustment is, therefore, made under exact normal operating conditions.

It will be apparent from the above description that I have provided novel means for easily and readily effecting an accurate adjustment of the primary air entering the burner structure, which adjustment can be made inde pendently of and without disturbing the physical and operational relationships existing between the various elements of the burner structure and casing under normal operating conditions. Thus, the invention not only provides a simple means of adjustment but also afiords much greater accuracy in the control of the primary air supply than could be accomplished in prior structures.

While I have illustrated my invention in connection with a unit heater structure or the like, it is believed apparent that the invention is readily adaptable for use in substantially any type of gas burner which is enclosed in a housing or casing as, for example, gas furnaces and other gas heating devices. Likewise, it is believed apparent that the specific details of construction of the adjustable air intake structure will depend to a large extent on the particular construction and arrangement of elements in the heating device to which it is to be applied. Similarly, while I have illustrated the invention in connection with a combination manifold and air inspirating structure, such as that disclosed in my co-pending application heretofore referred to, the invention may be readily applied to burner structures of substantially any type whether constructed in the form of castings or in the form of stampings, as illustrated.

Having thus described my invention, it is obvious that various immaterial modifications may be made in the same without departing from the spirit of my invention; hence, I do not wish to be understood as limiting myself to the exact form, construction, arrangement, and combination of parts herein shown and described or uses mentioned.

What I claim as new and desire to secure by Letters Patent is:

A gas heating device comprising a casing adapted to contain a heat exchanger, a hollow gas burner structure comprising a tubular burner manifold, tubular burners operatively connected to the tubular burner manifold, and a gas discharge tube including a nozzle operatively mounted with respect to the tubular burner manifold, said hollow gas burner structure positioned and operatively mounted within the casing and including an air inspirating tube, said air inspirating tube concentrically mounted within the tubular burner manifold and operatively connected thereto, one end of said tubular burner manifold and contiguous end of said air inspirating tube at the inlet opening thereof being peripherally aflixed together, a closure disc provided with an opening aflixed to the inlet end of said air inspirating tube, a closure member provided with an opening complementally formed to that of said closure disc, said gas discharge tube being operatively mounted with respect to the outer inlet end of the air inspirating tube for the discharge of gas therein along with the inspirated air, said closure member being complementally formed to said closure disc and comprising a tubular portion, said tubular portion of said closure member extending through an opening in said casing and in surrounding relation to said gas discharge tube and being accessible from the exterior thereof for adjusting said closure member, said closure disc and closure member being concentrically mounted with respect to the axis of the air inspirating tube, spring means operatively mounted on said tubular portion of said closure member, the inner end of said spring means operatively engaging the outer face of said closure member and the outer end of said spring means operatively engaging the casing contiguous to the opening therein through which the tubular portion extends for biasing the closure member against the closure disc in operative 5 relationship, said closure member and tubular portion thereof being rotatably adjustable with respect to the gas discharge tube, whereby the amount of air admitted to the burner interior may be varied without disturbing the operative relation between the casing and burner. 10

References Cited in the file of this patent UNITED STATES PATENTS 1,596,452 Reeves Aug. 17, 1926 15 6 Shaw Oct. 15, 1929 Carnahan July 14, 1931 Stark Sept. 6, 1932 Madison Nov. 22, 1932 Robbins Nov. 7, 1939 Beam Feb. 13, 1940 Kester Dec. 5, 1944 Kennedy Dec. 11, 1951 Kennedy Oct. 20, 1953 Solomon June 22, 1954 

